猪血管内皮细胞α-Gal对人外周血淋巴作用初探

超急性排斥反应克服后，异种移植物将面临血管性和细胞性排斥。血管内皮是免疫排斥的主要场所，异种移植免疫中血管内皮细胞的作用以及其携带的αＧａｌ在超急性排斥后免疫反应中的作用研究尚少。通过混合淋巴细胞反应（ＭＬＲ），以同种异体ＭＬＲ为对照，对异种（内江猪→人）外周血淋巴细胞（ＰＢＬＣ）混合反应和内江猪血管内皮细胞（ＰＡＥＣ）人ＰＢＬＣ混合反应进行研究，同时考察α半乳糖基酶消化后ＰＡＥＣ对人ＰＢＬＣ的刺激性。结果表明：异种ＭＬＲ增殖较相应的同种异体ＭＬＲ弱，可能与在异种周围淋巴细胞ＭＬＲ中以间接呈递为主有关；ＰＡＥＣ作为刺激细胞的ＭＬＲ增殖极强，可能与ＰＡＥＣ本身是抗原呈递细胞且抗原呈递以直接呈递为主有关；αＧａｌ引起增殖，可能与其在体内数量多、与生物大分子结合可成为全抗原有关，提示该抗原可能也是超急性排斥后排斥反应的靶抗原；去除ＰＡＥＣ表面αＧａｌ后，仍可诱发人Ｔ细胞反应，提示可能还存在其它超急性排斥后抗原。

EACTIVITY OF HUMAN PERIPHERAL BLOOD LYMPHOCYTE TO α-Gal ON PORCINE AROTIC ENDOTHELIAL CELL

After escaping from the hyperacute rejection (HAR), the xenograft has to be faced the challenge of acute vascular, acute cellular and even chronic rejection. Endothelial cells have been confirmed as a kind of antigen processing cell (APC) in allo-rejection. The porcine aortic endothelial cell (PAEC) expressed SLA-II and B7 which are the characteristics of professional APC. PAEC also has plenty of alpha-Gal residues, whether the antigen play any role in the post-HAR is still unknown. Human and porcine peripheral blood lymphocyte (PBLC) were isolated and divided into two parts, one for the effectors and the another were incubated with mitomycin C (MMC) as stimulators. The two kinds of PBLC were mixed-cultured within five days. Cultured PAEC from NJZ Pig was incubated with MMC and divided into two: One digested with alpha-galactosidase. The two kinds of PAEC were taken as stimulators to mixed-culture with human PBLC for five days. All the proliferation was detected with 3H-TdR intermingled in the system. The results showed that allo-MLR was stronger than xeno-MLR in the cases. The proliferation was much stronger when PAEC was used as the stimulator than that of porcine PBLC. However, the response was remarkably decreased after the digestion of alpha-Gal with alpha-galactosidase. The conclusion was that the low response of porcine-to-human MLR in vitro might be related to the predominant indirect pathway of antigen recognition in this system. While PAEC was used as the stimulator the proliferation in MLR was stronger which might be concerned that PAEC itself was an APC as well as xeno-antigen sources, thus the direct pathway was predominant and worked more efficiently. The alpha-Gal might induce T cell proliferation through the linkage with the biological big molecules working as a complete antigen. The other post-HAR antigen might also exist in PAEC such as SLA-II, etc.